Wellhead equipment including back pressure valve and removal tool



Sept. 19, 1944.-

WELL HEAD EQUIPMENT INCLUDING BACK Patented Sept. 19, 1944 WELLHEAD EQUIPMENT INCLUDING BACK PRESSURE VALVE AND REMOVAL TOOL John R. Yancey, Houston, Tex., assignor to Gray Tool Company, Houston, Tex., a corporation.

of Texas application september s, 1942, semi No. 45mm (ci. iss- 15) Sclalms.

' described, for example, in Patents No. 2,148,327,

to Smith, et al., and No. 2,241,288, to Yancey, a

back pressure valve is installed. in the uppei" end of the tubing line before washing, and thereafter has to be removed to permit the well to ilow. The removal operation involves the uncoupling of the valve from the tubing line and its lifting through control equipment thereabove. The object of the present invention is to provide means whereby the removal of the valve may be readily and safely accomplished with the utilization of well pressure as the lifting force. The invention relates in particular to a tool associable with standard well head assemblies for carrying out the stated object, the tool in one case being entirely self-contained, and in another, requiring a specially equipped back pressure valve, which latter is also a part of the invention.

The invention is shown in practical embodiment in the accompanying drawing, to which reference will now be made.

In the drawing:

Figure 1 is a vertical section of well head equipment in accordance with the invention, the back pressure valve appearing in elevation.

Figure 2 is an enlargement of a portion of Figure 1 with the back pressure valve appearing in axial section, and

Figure 3 is a fragmentary section of a modied form of valve andvtool.

Referring to Figures l and 2, reference numeral I designates a casing head which. through a hanger II, supports a string of casing I2. Secured on top of the casing head is a tubing head I3 which, through a hanger I4 and a bushing I5, supports a string of tubing I6. Secured on head I3, is a master valve I1, and on the latter is secured a flow manifold I8, here shown as being of the type disclosed in Patent No. 2.043.428. to Cullen.

The bushing I5 has a right hand threaded bottom socket in which the upper end of the top tubing section is threaded, and the bushing has top external right hand threads engaged with internal threads of the hanger I4 for the support of the tubing. At its upper end the bushing has internal right hand threads engageable by a. lifting tool, and therebelow, at its intermediate portion, hasv internal left hand threads I9. The bushing is constricted below the threads I9 to provide an upwardly faced bevelled shoulder 20.

Reference numeral 2l designates a back pressure valve, here shown as comprising a tubular body made up of an upper section 22, an intermediate section 23, and a bottom section 24 which has lateral slots. Two upwardly springpressed valves 25 and 26 cooperate respectively with seats 21 and 23. The upper end of section 22 is enlarged and isvprovided externally with left hand threads 23 for engagement with the left hand threads I3 of the bushing, the bottom of the enlargement providing a bevelled annular shoulder 30 adapted to seat` against the shoulder 20 to form a seal when the parts are assembled as in Figure 2. 'I'he upper end oi section 22 is provided with right hand internal threads 3|. Below the top enlargement of section 22 the body is of such diameter as to provide now clearance between it and the tubing line, the tubing line being here contemplated as including the bushing I5.

The new tool, generally designated by the reference character T, comprises, a tting or yoke 32 having spaced apart top and bottom tubular portions 33 and 34 rigidly joined by a pair of bows 35. Portion 34 is threaded in a flange 36 which is bolted on manifold I3. Portions 33 and 34 are provided with coaxial bores in alignment with the passages of the manifold and master valve, and extending through these bores is a hollow polish rod 31, the bores being equipped at their adjacent ends with stuffing boxes 33 and 39 so as to prevent leakage around the rod. The rod is rotatable and longitudinally slidable in the packings. The bore of portion 33 is enlarged above the stuffing box and has threaded therein the lower end of a tube 40 whose upper end is closed by a bull plug or equivalent iitting 4I. A bleeder valve 42 has a nipple portion 43 threaded in a radial bore of portion 33 between the stuffing box and the lower end of tube 40, the bleeder valve being thus carried by the yoke 32 in aY manner not to interfere with the removal and replacement of tube 40 and yet to communicate with the closed chamber defined by the tube and adjacent bore portion of portion 33.

The polish rod 31 is open throughout and its upper end is always in communication with the interior of the closed chamber.' The lower end of the polish rod is provided with right hand threads 44 engageable with the internal threads 3| of the back pressure valve, and above the threds 4I the rod 1S. BIDYQid with a side opening s. .l e l 1 When valve 2l is to be removed, the tool is set in position as shown in Figure 1. The polish rod at this time projects only slightly below ilange 36, the tube 40 being suillciently long to accommod-ate the upper portion of the rod. With the tool in place, the exposed portion of the rod between the stufnng boxes is gripped and the rod is lowered until its threads meet the threads 3| oi' the back pressure valve. A tong is now applied to the rod and the rod is turned to engage the threads. When the lower end or the rod strikes the shoulder at the base of threads 3l the back pressure valve is forced to participate in the right hand rotation ofthe rod and the latter. which was previously lowering, will now be seen to rise as the back pressure valve threads out of bushing I5, this occurring by reason of the fact that the threads I9 and 29 are left hand. As soon as the valve starts to rise, shoulder 30 moves away from shoulder 29 of the bushing and pressure will pass between threads I9 and 29, through opening 45, and thence through the polish rod to the chamber 40, so that the pressure above and below the back pressure valve is equalized. When the valve has been threaded out of the bushing the bleeder valve 42 may be opened so that the pressure becomes unbalanced and the back pressure valve and the polish rod will be forced upwardly. Inasmuch as the flow capacity of the bleeder valve will ordinarily be such that if opened wide the pressure below the back pressure actas?? ly take place. The opening or openings 49 are of the same total capacity as the opening 45 of the nrst embodiment, and the opening 45 is omitted from the polish rod 41 of Figure 3.

It should be noted that an important feature of the invention resides in the elimination of external pipes or pressure fittings which are apt to become broken or give trouble under the rough tratment generally accorded such equipment in oil fields. This is made possible by the utilization of the hollow polish rod itself as means for the transmission of iiuid pressure to the top of the valve would force it and the polish rod violently upwardly. the opening is made of such ilow capacity asto act as a choke under these circumstances. In other words, the capacity of opening 45 is such that regardless of the manipulation of the bleeder valve the pressure cannot be unbalanced to such an extent as to cause rapid upward movement of the back pressure valve and polish rod. 'Ihe flow capacity of opening 45 is approprlately less than the maximum flow capacity of the bleeder valve.

The upward movement continues until the t0p of the back pressure valve strikes the bottom of flange 38, whereupon the bleeder valve is closed. When this occurs, the bottom of the back pressure valve is above the gate of the master valve I1 so that the latter can be closed and the tool, together with the back pressure valve, removed from the manifold I8.

It will be seen that in the described operation the manifold merely serves as a spacer member and that other spacer means might be used. However, according to the invention it is preferred to use the manifoldas a matter of economy and speed since after the removal tool has been taken away the manifold is already in position for use in the manner described in the abovementioned patent to Cullen.

Once in a great while it might happend that the threads I9 and 29 would bind in such a manner as-to prevent the immediatepassage of pressure iluid. Any such diillculty can be avoided by the use of the modiiled back pressurevalve shown in Figure 3. According to this gure, the upper section 22a of the back pressure valve is provided with one or more openings 4l which extend through the walls of the section from its interior to a point or points at its exterior above the tool. 'I'he only external pressure fitting in the tool is the nipple 43 and even if this should become broken olf, no damage could occur since the choke effect of ports 45 or 46 would prevent too rapid rising of the polish rod.

From the standpoints of construction and hani size. fittings which are usually at hand in the iield. The polish rod may be formed in several sections and the entire assembly may thus be easily handled and assembled at the well.

It will be understood that the disclosed apparatus is not limited to use in completing a new well since it might also be used, for example, to remove a back pressure valve from a well which had been previously flowed and then plugged for some reason. Nor is the invention limited to the specific form and arrangement of parts disclosed, variations as to these being contemplated under the following claims. i

I claim:

1. A tool for use in removinga back pressure valve from a tubing line, said tool comprising a ttlng provided with spaced apart aligned bores each provided with a packing, said fitting being attachable to a well head assembly, a hollow polish rod rotatable and longitudinally slidable in said packings and exposed between said bores for manipulation, means for engaging one end of said rod with said valve whereby to be able to turn and lift the valve, means defining a closed chamber in connection with said iitting at the other end of said rod, said rod having a. side opening therein adjacent its valve-engaging end through which pressure can enter and pass to said chamber, and a bleeder valve in connection with said chamber.

2. A tool for use in removing a back pressure valve from a tubing line, said tool comprising a iltting provided with spaced apart aligned bores each provided with a packing, said tting being attachable to a well head assembly, a hollow polish rod rotatable and longitudinally slidable in said packings and exposed between said bores for manipulation. means for engaging one end of said rod with said valve whereby to be able to turn and lift the valve, means deilning a closed chamber in connection with said fitting at the other end of said rod, said rodhaving a side opening therein adjacent its valve-engaging end through which pressure can enter and pass to said chamber, and a bleeder valve in connection with said chamber. said side opening having a ilow capacity less than the maximum ow capacity of said bleeder valve.

3.`A tool for removing a back pressure valve from a tubing line, said tool comprising a iitting provided with spaced-apart upper and lower aligned bores each provided with a packing, the

upper bore including a portion above its packing, said tting being attachable to a well head assembly, a hollow polish rod rotatable and longitudinally slidable in said packings and exposed between said boresfor manipulation, means for engaging one end of said rod with said valve whereby to be able to turn and lift the valve, a. tube secured to the itting and extending upwardly from said upper bore in alignment therewith, means closing the upper end of said tube, said tube being adapted to receive the upper portion of said rod, and a bleeder valve on the ntting communicating with the upper portion of the upper bore.

4. For use with a. well head assembly comprising a tubing head, tubing supported from said head by means including a bushing having internal threads and an annular upwardly faced shoulder below said threads, a back pressure valve including a tubular body having threads engaging the bushing threads and a shoulder sealing against the bushing shoulder, saidvbody having at its upper end internal threads which run oppositely to the iirst-mentioned body threads, and a master valve on the tubing head; a tool for removing said back pressure valve, said tool comprising a tting having aligned spaced-apart bores each provided with a packing, said iitting being securable above said master valve in iluidtight relation therewith and with its bores in vertical alignment with the passage of the master valve, a hollow polish rod rotatable and longitudinally slidable in said packings, said rod having at one end threads engageable with the internal threads of said back pressure valve, a closed tube secured to the upper end of said tting and adapted to receive the upper end of said rod, a bleeder valve operatively associated with said tube, andan opening provided above said body shoulder to the interior of said rod rendered accessible to well pressure when the body shoulder is unseated from the bushing shoulder in the removal operation so that pressure above and below the back pressure valve will be equalized and can be unbalanced under the control of said bleeder valve to cause the polish rod and back pressure valve to lift to a position enabling the master valve to be closed.

5. Well head equipment comprising a tubing head, tubing supported from said head vby means includinga bushing having internal threads and an ann ar upwardly faced shoulder below said threads, a back pressure valve including a. tubular body having threads engaging the bushing threads and a shoulder sealing against the bushing shoulder, said body having at its upper end internal threads which run oppositely to the iirstmentioned body threads, a master valve on the tubing head, a spacer member on the master valve having a passage registering with the master valve passage, a fitting on the spacer member having coaxial spaced-apart bores each provided with a packing and in alignment with the spacer member passage, a hollow polish rod rotatable and longitudinally slidable in said packings, said rod having at one end threads engageable with the internal threads of said back pressure valve, a closed tube secured to the upper end of said fitting and adapted to receive the upper end of said rod, a bleeder valve operatively associated with said tube, and an opening provided above said body shoulder to the interior of said rod rendered accessible to well pressure when the body shoulder is unseated from the bushing shoulder in the removal operation so that pressure above and below the back pressure valve will be equalized and can be unbalanced under the control of said bleeder valve to cause the polish rod and back pressure valve to lift to a position enabling the master valve tobe closed.

6. Structure according to claim 5 wherein the spacer member is constituted by a iiow manifold.

7. A tool for removing a back pressure valve from a tubing line, said tool comprising a hollow polish rod, means for'engaging one end of said rod with the valve whereby to turn and lift the latter, means defining a closed chamber with which the other end of the rod communicates, means for connecting said chamber to a well head assembly, said rod having a side opening adjacent said one end through which well pressure can enter and pass to said chamber, and a bleeder valve in connection with said chamber, said rod having a portion outside of said chamber which may be engaged for manipulation.

8. Structure according to claim '1 wherein said opening has a flow capacity less than the maximum flow capacity of said bleeder valve.

- JOHN R. YANCEY. 

